1. Field of the Invention
The present invention relates to an improved closure device for bottles or similar containers and, more particularly, to a closure device including means to withdraw liquid from the sealed bottle.
2. Description of Prior Art
In the manufacture of integrated microelectronic components, commonly referred to as semiconductor chips, it is imperative to provide carefully controlled processing conditions to maximize the yield of acceptable products. In typical fabrication processes for microelectronic components, a batch of several hundred or more individual semiconductor chips may undergo the same manufacturing process at the same time. Accordingly, any processing upset or error can render useless a large number of potential products. This is especially true, for example, in photolithographic processes where silicon substrates are chemically etched to form topographical patterns which are essential to operation of the microelectronic components.
In conjunction with chemical etching of semiconductor substrates, it is well-known to coat certain portions of the silicon substrate with a thin layer of polymeric liquid known as photoresist. Upon exposure to ultraviolet radiation, the photoresist rapidly solidifies to form a protective layer on the selectively coated portions of the substrate to protect those portions from chemical attack during subsequent etching. Such coatings of photoresist must be continuous over the area to be protected, otherwise a portion of the coated area will undergo etching and the electronic component will likely be rendered valueless. The causes of discontinuities in photoresist coatings have been found to include impurities or particles which are introduced to the process as the photoresist is dispensed from container or reservoir bottles. Accordingly, it is important in the fabrication of semiconductor microelectronic components to minimize the opportunity for particulate impurities to find their way into photoresist liquid.
In a typical microelectronic fabrication operation, photoresist is dispensed periodically by pumping from relatively small bottles. The practice of using small bottles relates to the expense, toxicity and shelf life of the chemical, as well as other factors. Because the individual containers for the photoresist liquid are relatively small, it is necessary to frequently replace the bottles in the dispensing equipment or replenish their contents. Heretofore, the replacement or replenishment operations have often permitted particles to enter the bottles. For example, it has been found that the photoresist may solidfy in the bottles at locations on or near the caps so that, when the cap is removed or replaced, some of the solidified material may flake away and fall into the photoresist liquid. Such flakes may not completely dissolve prior to being pumped out of the bottles and may cause imperfections in the photoresist coatings applied to the microelectronic components.